Nanomaterials describe, in principle, materials of which a single unit is sized (in at least one dimension) between 1 to 1000 nanometres (10−9 meter) but usually is 1 to 100 nm (the usual definition of nanoscale).
Aside from being a public health hazard, particles in the atmosphere affect climate. New data mining and analysis methods are shedding light on the role of one of the most important components, black carbon.